Seating portion of collapsible chair



FIG. 1 is a perspective view of a seating portion of collapsible chair, showing my new design; the broken lines are for environmental purposes only and form no part of the claimed design;

FIG. 2 is a top plan view;

FIG. 3 is a front elevational view;

FIG. 4 is a bottom plan view;

FIG. 5 is a rear elevational view;

FIG. 6 is a left side elevational view; and,

FIG. 7 is a right side elevational view. 

The ornamental design for seating portion of collapsible chair, as shown. 